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        Working with Go
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      <h1>Object Oriented Programming</h1>

<p>Go does not have objects and classes, so is not a true object oriented programming. However, you can add methods to types. This gives you most of the same ability without the added complexity of full OOP.</p>

<p>A method is a function with a <em>receiver</em> defined first. Using the <code>Dog</code> type from the <a href="/structs.html">structs example</a>.</p>

<pre><code class="language-go">package main

import &quot;fmt&quot;

type Dog struct {
	Name  string
	Color string
}

func (d Dog) Call() {
	fmt.Printf(&quot;Here comes a %s dog, %s.\n&quot;, d.Color, d.Name)
}

func main() {

	// create instance of dog
	Spot := Dog{Name: &quot;Spot&quot;, Color: &quot;brown&quot;}

	// call object method
	Spot.Call()
}
</code></pre>

<h2>Limitations</h2>

<p>You can define methods on custom types, but are limited to types that are defined in the same package as the method. So you cannot define a method on built-in types, you would first need to extend.</p>

<pre><code class="language-go">package main

import &quot;fmt&quot;

type MyInt int

func (i MyInt) Double() MyInt {
	return i * 2
}

func main() {
	x := MyInt(3)
	fmt.Println(x.Double())
}
</code></pre>

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